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Perfect unison
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In music, unison is two or more musical parts sounding the same pitch or at an octave interval, usually at the same time.

Music form of art using sound

Music is an art form and cultural activity whose medium is sound organized in time. General definitions of music include common elements such as pitch, rhythm, dynamics, and the sonic qualities of timbre and texture. Different styles or types of music may emphasize, de-emphasize or omit some of these elements. Music is performed with a vast range of instruments and vocal techniques ranging from singing to rapping; there are solely instrumental pieces, solely vocal pieces and pieces that combine singing and instruments. The word derives from Greek μουσική . See glossary of musical terminology.

Part (music) section of a musical composition

A part generally refers to a single strand or melody or harmony of music within a larger ensemble or a polyphonic musical composition. There are several senses in which the word is often used:

Pitch (music) perceptual property in music

Pitch is a perceptual property of sounds that allows their ordering on a frequency-related scale, or more commonly, pitch is the quality that makes it possible to judge sounds as "higher" and "lower" in the sense associated with musical melodies. Pitch can be determined only in sounds that have a frequency that is clear and stable enough to distinguish from noise. Pitch is a major auditory attribute of musical tones, along with duration, loudness, and timbre.


Rhythmic patterns which are homorhythmic are also called unison. [1]

Rhythm aspect of music

Rhythm generally means a "movement marked by the regulated succession of strong and weak elements, or of opposite or different conditions". This general meaning of regular recurrence or pattern in time can apply to a wide variety of cyclical natural phenomena having a periodicity or frequency of anything from microseconds to several seconds ; to several minutes or hours, or, at the most extreme, even over many years.


In music, homorhythm is a texture where there is a "sameness of rhythm in all parts" or "very similar rhythm" as would be used in simple hymn or chorale settings. Homorhythm is a condition of homophony. All voices sing the same rhythm. This texture results in a homophonic texture, which is a blocked chordal texture. Homorhythmic texture delivers lyrics with clarity and emphasis. Texture in which parts have different rhythms is heterorythmic or heterometric.

Interval of the unison

Inverse octave
Other namesperfect unison, prime, perfect prime
Semitones 0
Interval class 0
Just interval 1:1
Equal temperament 0
24 equal temperament 0
Just intonation 0

Two pitches that are the same or two that move as one. [2]

Unison or perfect unison (also called a prime, or perfect prime [3] ) may refer to the (pseudo-)interval formed by a tone and its duplication (in German, Unisono, Einklang, or Prime), for example C–C, as differentiated from the second, C–D, etc. In the unison the two pitches have the ratio of 1:1 or 0 half steps and zero cents. Although two tones in unison are considered to be the same pitch, they are still perceivable as coming from separate sources, whether played on instruments of a different type: Loudspeaker.svg play unison on C, piano and guitar  ; or of the same type: Loudspeaker.svg play unison on C, two pianos  . This is because a pair of tones in unison come from different locations or can have different "colors" (timbres), i.e. come from different musical instruments or human voices. Voices with different colors have, as sound waves, different waveforms. These waveforms have the same fundamental frequency but differ in the amplitudes of their higher harmonics. The unison is considered the most consonant interval while the near unison is considered the most dissonant. The unison is also the easiest interval to tune. The unison is abbreviated as "P1".

In music theory, an interval is the difference in pitch between two sounds. An interval may be described as horizontal, linear, or melodic if it refers to successively sounding tones, such as two adjacent pitches in a melody, and vertical or harmonic if it pertains to simultaneously sounding tones, such as in a chord.

Major second musical interval

In Western music theory, a major second is a second spanning two semitones. A second is a musical interval encompassing two adjacent staff positions. For example, the interval from C to D is a major second, as the note D lies two semitones above C, and the two notes are notated on adjacent staff positions. Diminished, minor and augmented seconds are notated on adjacent staff positions as well, but consist of a different number of semitones.

The cent is a logarithmic unit of measure used for musical intervals. Twelve-tone equal temperament divides the octave into 12 semitones of 100 cents each. Typically, cents are used to express small intervals, or to compare the sizes of comparable intervals in different tuning systems, and in fact the interval of one cent is too small to be heard between successive notes.

However, the unison was questioned by Zarlino as an interval for lacking contrast and compared to a point in geometry:

Gioseffo Zarlino Italian composer

Gioseffo Zarlino was an Italian music theorist and composer of the Renaissance. He was possibly the most famous European music theorist between Aristoxenus and Rameau, and made a large contribution to the theory of counterpoint as well as to musical tuning.

Point (geometry) fundamental object of geometry: locus within which we can distinguish no other locus than itself

In modern mathematics, a point refers usually to an element of some set called a space.

Equality is never found in consonances or intervals, and the unison is to the musician what the point is to the geometer. A point is the beginning of a line, although, it is not itself a line. But a line is not composed of points, since a point has no length, width, or depth that can be extended, or joined to another point. So a unison is only the beginning of consonance or interval; it is neither consonance nor interval, for like the point it is incapable of extension. [4]

Line (geometry) straight object with negligible width and depth

The notion of line or straight line was introduced by ancient mathematicians to represent straight objects with negligible width and depth. Lines are an idealization of such objects. Until the 17th century, lines were defined as the "[…] first species of quantity, which has only one dimension, namely length, without any width nor depth, and is nothing else than the flow or run of the point which […] will leave from its imaginary moving some vestige in length, exempt of any width. […] The straight line is that which is equally extended between its points."

"In unison"

"Twinkle, Twinkle, Little Star" melody doubled in unison.
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"Twinkle, Twinkle, Little Star" melody doubled in unison. Loudspeaker.svg Play   clarinet & pizz. violin
"Twinkle, Twinkle, Little Star" melody doubled in four octaves.
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Several singers singing a melody together. [2]

In orchestral music unison can mean the simultaneous playing of a note (or a series of notes constituting a melody) by different instruments, either at the same pitch; or in a different octave, for example, cello and double bass (all'unisono). Typically a section string player plays unison with the rest of the section. Occasionally the Italian word divisi (meaning divided, abbrev. div.) marks a point where an instrumental section, typically the first violins, is to be divided into two groups for rendering passages that might, for example, include full chords. Thus, in the divisi first violins the "outside" players (nearer the audience) might play the top note of the chord, while the "inside" seated players play the middle note, and the second violins play the bottom note. At the point where the first violins no longer play divisi, the score may indicate this with unison (abbrev. unis.).

When several people sing together, as in a chorus, the simplest way for them to sing is to sing in "one voice", in unison. If there is an instrument accompanying them, then the instrument must play the same notes being sung by the singers (in order for there to be unison). Otherwise the instrument is considered a separate "voice" and there is no unison. If there is no instrument, then the singing is said to be a cappella . Music in which all the notes sung are in unison is called monophonic.

From this sense can be derived another, figurative, sense: if several people do something "in unison" it means they do it simultaneously, in tandem, in lockstep. Related terms are "univocal" and "unanimous".

Monophony could also conceivably include more than one voice which do not sing in unison but whose pitches move in parallel, always maintaining the same interval of an octave. A pair of notes sung one or a multiple of an octave apart are almost in unison, due to octave equivalency.

When there are two or more voices singing different notes, this is called "part singing". If they are singing notes at different pitches but with the same rhythm this is called homophony. An example is a barbershop quartet or a choir singing a hymn. If each voice is singing an independent line (either the same melody at a different time, or different melodies) this is called polyphony.


On synthesizers, the term unison is used to describe two or more oscillators that are slightly detuned in correspondence to each other, which makes the sound fatter. This technique is so popular that some modern virtual analog synthesisers have a special oscillator type called "super saw" or "hyper saw" that generates several detuned sawtooth waves simultaneously.

See also


  1. Rushton, Julian. "Unison (prime)]". Grove Music Online . Oxford Music Online. (subscription needed)
  2. 1 2 Benward, Bruce, and Marilyn Nadine Saker (2003). Music: In Theory and Practice, Vol. I, seventh edition, p. 364. Boston: McGraw-Hill. ISBN   978-0-07-294262-0.
  3. Benward & Saker (2003), p. 53.
  4. Thomas Street Christensen (2004). Rameau and musical thought in the Enlightenment, p. 76. ISBN   978-0-521-61709-3.

Further reading

Related Research Articles

Counterpoint relationship between voices that are harmonically interdependent (exhibiting polyphony) yet independent in rhythm and contour

In music, counterpoint is the relationship between voices that are harmonically interdependent (polyphony) yet independent in rhythm and contour. It has been most commonly identified in the European classical tradition, strongly developing during the Renaissance and in much of the common practice period, especially in the Baroque. The term originates from the Latin punctus contra punctum meaning "point against point".

Musical tuning umbrella term for the act of tuning an instrument and a system of pitches

In music, there are two common meanings for tuning:

In music, an octave or perfect octave is the interval between one musical pitch and another with double its frequency. The octave relationship is a natural phenomenon that has been referred to as the "basic miracle of music", the use of which is "common in most musical systems". The interval between the first and second harmonics of the harmonic series is an octave.

Perfect fourth musical interval

A fourth is a musical interval encompassing four staff positions in the music notation of Western culture, and a perfect fourth is the fourth spanning five semitones. For example, the ascending interval from C to the next F is a perfect fourth, because the note F is the fifth semitone above C, and there are four staff positions between C and F. Diminished and augmented fourths span the same number of staff positions, but consist of a different number of semitones.

Perfect fifth musical interval

In music theory, a perfect fifth is the musical interval corresponding to a pair of pitches with a frequency ratio of 3:2, or very nearly so.

Relative pitch is the ability of a person to identify or re-create a given musical note by comparing it to a reference note and identifying the interval between those two notes. Relative pitch implies some or all of the following abilities:

This is a list of musical terms that are likely to be encountered in printed scores, music reviews, and program notes. Most of the terms are Italian, in accordance with the Italian origins of many European musical conventions. Sometimes, the special musical meanings of these phrases differ from the original or current Italian meanings. Most of the other terms are taken from French and German, indicated by "Fr." and "Ger.", respectively.

Ear training or aural skills is a skill by which musicians learn to identify, solely by hearing, pitches, intervals, melody, chords, rhythms, and other basic elements of music. The application of this skill is analogous to taking dictation in written/spoken language. As a process, ear training is in essence the inverse of sight-reading, the latter being analogous to reading a written text aloud without prior opportunity to review the material. Ear training is typically a component of formal musical training and is a fundamental, essential skill required in music schools.

Gamelan jegog

Jegog is a form of gamelan music indigenous to Bali, Indonesia, played on instruments made of bamboo. The tradition of jegog is centered in Jembrana, a region in Western Bali. In recent years jegog has started to become popular in other regions of Bali with a few groups being established in central Bali to entertain tourists. International interest has been spread by tourists visiting Bali and by recordings. There are virtually no ensembles outside of Bali with the exception of at least two groups in Japan, one in the United States and one in Germany. Jegog music is very fast, loud, rhythmic and precise. Pieces last from a few minutes to as long as thirty minutes.

Musical acoustics or music acoustics is a branch of acoustics concerned with researching and describing the physics of music – how sounds are employed to make music. Examples of areas of study are the function of musical instruments, the human voice, computer analysis of melody, and in the clinical use of music in music therapy.

Consecutive fifths

In music, consecutive fifths, or parallel fifths, are progressions in which the interval of a perfect fifth is followed by a different perfect fifth between the same two musical parts : for example, from C to D in one part along with G to A in a higher part. Octave displacement is irrelevant to this aspect of musical grammar; for example, parallel twelfths are equivalent to parallel fifths.

Consonance and dissonance categorizations of simultaneous or successive sounds

In music, consonance and dissonance are categorizations of simultaneous or successive sounds. Consonance is associated with sweetness, pleasantness, and acceptability; dissonance is associated with harshness, unpleasantness, or unacceptability.

Imitation (music) music

In music, imitation is the repetition of a melody in a polyphonic texture shortly after its first appearance in a different voice. The melody may vary through transposition, inversion, or otherwise, but retain its original character. The intervals and rhythms of an imitation may be exact or modified; imitation occurs at varying distances relative to the first occurrence, and phrases may begin with voices in imitation before they freely go their own ways.

Voicing (music) manner in which one distributes, or spaces, notes and chords among the various instruments or simultaneous vertical placement of notes in relation to each other

In music theory, voicing refers to one of two closely related concepts:

  1. How a musician or group distributes, or spaces, notes and chords on one or more instruments
  2. The simultaneous vertical placement of notes in relation to each other; this relates to the concepts of spacing and doubling
Music and mathematics

Music theory has no axiomatic foundation in modern mathematics, yet the basis of musical sound can be described mathematically and exhibits "a remarkable array of number properties". Elements of music such as its form, rhythm and metre, the pitches of its notes and the tempo of its pulse can be related to the measurement of time and frequency, offering ready analogies in geometry.

In music theory, the word inversion has distinct, but related, meanings when applied to intervals, chords, voices, and melodies. The concept of inversion also plays an important role in musical set theory.

The term "four-part harmony" refers to music written for four voices or for some other musical medium—four musical instruments or a single keyboard instrument, for example—where the various musical parts can give a different note for each chord of the music.

Interval ratio ratio of the frequencies of the pitches in a musical interval

In music, an interval ratio is a ratio of the frequencies of the pitches in a musical interval. For example, a just perfect fifth is 3:2, 1.5, and may be approximated by an equal tempered perfect fifth which is 27/12. If the A above middle C is 440 Hz, the perfect fifth above it would be E, at (440*1.5=) 660 Hz, while the equal tempered E5 is 659.255 Hz.

Abbreviations in music are of two kinds, namely, abbreviations of terms related to musical expression, and the true musical abbreviations by the help of which certain passages, chords, etc., may be notated in a shortened form, to the greater convenience of both composer and performer. Abbreviations of the first kind are like most abbreviations in language; they consist for the most part of the initial letter or first syllable of the word employed—as for instance, p or f for the dynamic markings piano and forte, cresc. for crescendo, Ob. for oboe, Fag. for bassoon. This article is about abbreviations used in music notation. For abbreviations of terms related to musical expression and music in general, see Glossary of musical terminology.